Speedometer/Odometer Quit - Cruise still works. VSS or Speedo Head?

[subaruVWnut]

1999 Oubback Automatic AWD

 

My speedometer failed today....odometer stopped also. But the cruise still works and the engine still runs fine. No check engine light ...at least yet.

 

From reading previous posts on speedometer problems....(and if I'm interpreting the previous posts correctly )..it sounds like my symptoms point to the speedo head....rather than the sensor on the tranny...

 

Am I correct that a failure of the tranny sensor (VSS) usually generates an OBD-II error and the check engine light comes on.

 

Since my cruise control still works, engine is not in "limp" mode, and no CEL, the signs point to the speedo head.

 

Am I right or wrong.....other factors to consider ????

 

Warren C.

[Cougar]

If you have a flexible cable that ties to the speedometer then it may be broken. I don't think that will generate a code if you have that kind of design.

[mwatt]

If you have a flexible cable that ties to the speedometer then it may be broken. I don't think that will generate a code if you have that kind of design.

 

I'm afraid the days when cars had speedometer cables are long gone.....most American cars have had "VSS driven" speedometers since the late eighties or early nineties, and Subaru has not used a cable-driven speedometer in years, either.

[WAWalker]

Yep, speedo head. Very common on 99 OB.

[Cougar]

Thanks Mwatt. I didn't know when they changed over.

[MiniTransAm]

These were the same exact symptoms that my 99 OBW had. I just replaced the speedo head and it's working fine. Not a hard job to do yourself either. Took me an hour tops with fading sunlight.

 

You can even set your mileage on the new one if you like. that is kind of a PITA and you risk breaking some plastic clips. I'd just write the old mileage down and put it in your glove box or door jamb for when you get inspections done.

[itzik93]

1999 Oubback Automatic AWD

 

My speedometer failed today....odometer stopped also. But the cruise still works and the engine still runs fine. No check engine light ...at least yet.

 

From reading previous posts on speedometer problems....(and if I'm interpreting the previous posts correctly )..it sounds like my symptoms point to the speedo head....rather than the sensor on the tranny...

 

Am I correct that a failure of the tranny sensor (VSS) usually generates an OBD-II error and the check engine light comes on.

 

Since my cruise control still works, engine is not in "limp" mode, and no CEL, the signs point to the speedo head.

 

Am I right or wrong.....other factors to consider ????

 

Warren C.

 

Yep, its probably your speedo head. If your cruise control works and no check engine light appears then probably the "engine" of the head has died.

 

The speedo head is also a small computer that gets AC voltage from the VSS.

you can check the VSS by a volt-meter (on "AC" mode) and run the car (you can do it on jackstands or by driving it).

The small computer in the speedo head takes the AC voltage from the VSS and uses it for couple of things:

1. Run the Speedo needle (if you have needle...)

2. Run the odometer counter

3. Output singal to the ECU (for 2 reasons: 1-cruise control, 2-to prevet engine stall while stopping the car).